Laughlin , Robert B.

(1950–) American physicst

Laughlin was born in Visalia, California, and gained his PhD in physics in 1979 from the Massachusetts Institute of Technology. In 1989 he became professor of physics at Stanford University, where he did research on the fractional quantum Hall effect. For this work he shared the 1998 Nobel Prize for physics with Horst Störmer and Daniel Tsui, for explaining their discovery of a new form of quantum fluid with fractionally charged excitations.

Laughlin showed how electrons in a powerful magnetic field can condense to form a so-called ‘quantum fluid’ similar to those that occur in liquid helium and in superconductors. The theory derives ultimately from the Hall effect (the production of a voltage in a current-carrying conductor or semiconductor at right angles to a magnetic field), discovered in 1879 by the American physicist Edwin Hall. It occurs because electrons – the charge carriers – are deflected laterally in the magnetic field. A century later the German physicist Klaus von Klitzing discovered that in a powerful magnetic field at extremely low temperatures the Hall resistance of a semiconductor is quantized in integral ‘steps’.

Using even stronger magnetic fields and lower temperatures, Störmer and Tsui discovered more steps, called the fractional quantum Hall effect. A year later Laughlin theorized that the low temperature and powerful magnetic field forced the electrons to form a new type of quantum fluid. The addition of a single electron to this superfluid produced a number of fractionally charged quasiparticles, with the correct charges to account for the results of Störmer and Tsui.